This invention relates generally to photographic equipment for underwater use and more particularly to light sources used in underwater photography and the methods of making such light sources.
An apparatus for providing adequate lighting is vital to underwater photography. Strobe flash units adapted for underwater use must be waterproof and capable of withstanding the intense stresses encountered in deep water. Yet, they should also be as light-weight and compact as possible to permit easy handling. Further, the flash units should dissipate heat as rapidly as possible to prolong the operating life of the unit.
In the past, a few underwater flash units, such as those described in U.S. Pat. Nos. 2,996,966 and 3,252,393, have been available. However, they were relatively expensive and difficult to handle because of their substantial bulk. Another problem encountered with some known underwater flash units stemmed from the fact that air pockets were present between the flash unit and the casing. In some cases, there were even air pockets within the casing material. As the devices containing these air pockets were lowered to substantial depths in the water, structural failures frequently occurred due to the difference in the hydrostatic pressure and the pressure exerted by these air pockets. These structural failures would, of course, render the flash unit inoperative. In addition, the air pockets formed insulating layers which inhibited the dissipation of heat generated by the flash unit. As a consequence, the operating life of the underwater flash unit was substantially lessened.